Piston skirt expander



Dec. 10, 1935. R. w. PATON 2,023,613

' PISTON SKIRT EXPANDER Filed May 16,- 193 -5/MMWM am i, 9W5

Patented Dec. 10, 1935 I UNITED STATES PATENT OFFICE.

Perfect Circle Gompan corporation of Indiana y, Hagerstown, Ind. a

Application May 16, 1934, Serial No. 725,839

. 9 Claims. (01. 309-12) This invention relatesto means for expandingthe split skirt of a piston for internal combustion engines, and the like, to eliminate piston slapping, excessive oil consumption and blow-by and other defects.

One of the objects of the invention is to provide a novel piston skirt expander formed of fiat spring metal which is simple in construction, efficient in use and readily applicable to the piston skirt. 1

Another object is to provide an expander of the foregoing character which is provided with a novel arrangement of expanding formations well adapted for use with so-called T-slot pistons.

' A more specific object is to provide an expander having upper and lower sections which are provided with expansible formations adapted to cooperate with piston skirt walls having oppositelydisposed slots that extend, respectively, from the opposite ends of the piston skirt and only partly throughout the length .of such skirt.

Other objects and advantages will become apparent as this description progresses and by reference to the drawing wherein- I expander shown in the previous figures;

- piston formed preferably of aluminum alloy and Fig. is a separated perspective view of the upper section of the expander shown in Fig. 4; and

Fig. 6 is a perspective view of the lower section of the expander of Fig. 4.

The structure shown in the drawing includes a having a head In and a skirt I l which is separated from the head Ill throughout a portion of its circumference by a horizontal slot I2. The skirt II is provided with a vertically-extending slot I3 which extends from the upper end of the skirt only partially throughout the length of the latter as best shown in Fig. 1.- This upper end of this slot l3 joins with substantially the central portion of the head-separating slot I2 whereby the two slots I2 and I3 provide a T-shaped slot formation permitting expansion and contraction of the piston skirt as will be well understood. The piston skirt integrally supports piston pin bosses I4 which carry a piston pin l5.

In carrying out this invention, the skirt wall directly opposite the slot I3 is provided with another slot I6 which extends from the lower end of the piston skirt only partially throughout the length thereof as shown in Fig. 2. If the slot l6 5 is not normally provided in the piston skirt, it may be readily formed therein at the time of the servicing operation in which the expander is applied.

The expander includes an upper section I I and 10 a lower section l8, each'formed of a strip of spring steel bent to a rectangular-like closed figure shape. The free ends of the upper section are curled or curved to provide expansible and contractible skirt wall contacting portions I9. The rear or closed end of this section is bent inwardly as at providing spaced bends 2| and 22 which engage the piston skirt wall at points opposite the free ends I9. The lower sectionl8 is provided with similarly-formed and shaped free 20 ends 23 and bends 24. .The free ends I9, 23 and the bends 2|, 22, 24 are provided with rather sharp lips 25 which bite into the metal of the piston skirt and securely anchor the expander therein.

The upper expander section I! is provided with side portions 26 having downwardly-extending arms 21 adapted to be secured by rivets 28 (or other suitable fastening devices) to the side portions 29 of the lower section I8. The side por- 3Q tions 26 of the upper section are provided with aligned openings 30 which, in the assembled position of the expander, align with the openings 3| in the piston pin bosses l4 so that the piston pin I5 passes therethrough.

The free curved ends I9 of the upper section are adapted to engage the piston skirt wall adjacent the slot l3, and the curved ends 23 of the lower section are adapted to engage the skirt wall adjacent the slot I 6 (Fig. 3). To this end, and' 0 'in view of the vertical staggered relation of the opposed slots l3 and I6, the upper and lower sections are secured together in such a manner that the free ends I9 and 23 of these sections are lo- .cated at opposite ends of the expander. The 4 arrangement is such that the free ends of the lower section I8 are located beneath and in alignment with the closed end and the bends 2 I, 22 of the upper section; and the closed end and bends 24 of the lower section are beneath and in alignment with the free ends I9 of the upper section IT. The attachment arms 21 of the upper section are of such length that the end portions of the expander sections are spaced apart. This spacing is such that, when the expander is applied to the piston (Fig. 2), the closed end of the upper section I! abuts the skirt wall above the slot l6 with its free ends straddling the slot l3 at the other side of the skirt, and the closed end of the lower section I8 abuts the piston skirt beneath the lower end of the slot l3 with its free ends straddling the slot H3 at the other side of the skirt.

The expander is of such size and shape that, when it is contracted by hand or other means and placed within the skirt and then released, the opposite ends of the expander sections press firmly in opposite directions against the skirt wall, and the sides of the expander bow outwardly so that they seat firmly against and apply expanding pressure to the facing surfaces of the piston pin bosses I4. In this manner the skirt is expanded and it is maintained in expanded condition. By arranging the free ends of the upper and lower expander sections l1 and I8 alternately as described so as to cooperate with the staggered slots I3 and IS, the expansion action is substantially uniform and the avoidance of piston slap, excessive blow-by and oil consumption is accomplished in an efficient manner. The foregoing action isaided by the vertical bends 32 in each of the sections adjacent their respective side portions 28 and 29.

It will be understood that, while only one form of structure embodying the invention has been illustrated and described, other changes in details and arrangements of parts may be made without departing from the spiritand scope of the invention as defined by the claims which follow.

I claim:

1. A piston skirt expander which comprises a pair of sections each formed of a strip of spring metal bent to a generally polygonal shape with one end portion continuous and the other end portion provided with free ends, and means securely fastening said two sections together with the free end portion of one section vertically aligned with and spaced from the continuous end portion of the other section.

2. A piston skirt expander which comprises a pair of sections each formed of a strip of spring metal bent to a generally polygonal shape with one end portion formed continuous and the other end portion provided with free ends, one of said sections having its opposite sides extended downwardly and provided with openings to receive a piston pin or the like, and means for fixedly securing the lower ends of said side extensions to the other of said sections with the end portions of said latter section reversed with respect to the end portions of said one section.

3. A piston skirt expander which comprises a pair of sections each formed of spring metal to a generally rectangular shape and having free ends at only one end thereof, the sides of one of said sections being provided with openings to receive a piston pin, said sides being extended for securement to the sides of the other of said sections, and means fixedly securing said side portions of said sections together with the free ends thereof at opposite ends of the expander and with the adjacent ends of said sections vertically spaced apart.

4. A piston skirt expander which includes a pair of sections each formed from a strip of spring metal to a generally polygonal shape, each said section being continuous at one end portion with spaced apart wall-contacting points therein and being provided at its other end portion with free ends curved for expansible skirt wall engagement, the side walls of one of said sections being provided with extensions, and means securing the free ends of said extensions to the side walls of the other of said sections with the end por- 5 tions of said sections reversed with respect to each other and with the adjacent end portions of the secured sections vertically spaced apart.

5. In combination with a piston having a skirt with opposed and vertically staggered slots there- 10 in, of a spring metal expander within and extending crosswise ofsaid skirt and including a pair of attached sections each formed contiguous except for free ends at one end portion thereof, said free ends having expansible formations, 15 and said free ends of each section being disposed at opposite ends of the expander in vertically staggered fashion and engaging the interior of the piston skirt in straddle relation with respect to the respective of said vertically staggered slots. 20

6. In combination with a piston having a skirt with substantially diametrically opposed slots therein, one extending partially throughout the length of the skirt from the upper end thereof and the other extending partially throughout 25 the length of the skirt from the lower end thereof, of a spring metal expander in the form of a closed figure mounted crosswise within said skirt and including upper and lower sections secured together, said upper section being continuous at 30 one end portion and having a pair of free ends at its other end portion located to engage said skirt wall on opposite sides of said first-mentioned slot and said lower section being similarly formed and having its free ends located to en- 35 gage the wall of said skirt on opposite sides of said second mentioned slot.

'7. In combination with a piston having a skirt with opposed and vertically staggered slots therein, one of said slots extending from the upper end of said skirt and the other from the lower end of said skirt, of a spring metal expander mounted within said skirt and having up per and lower sections of general rectangular shape, each of said sections having one end 45 formed continuous and its other end provided with a pair of free ends, said sections being secured together with their respective free end portions at opposite ends of the expander, the ends of said sections being engaged with the skirt 50 wall with the free ends of said sections straddling the respective of said opposed slots.

8. In combination with a piston having a skirt with opposed and vertically staggered slots therein, one of said slots extending from the upper end of said skirt and the other from the lower end of said skirt, of a spring metal expander mounted within said skirt and having upper and lower sections of general rectangular shape, each of said sections having one end formed continu ous and its other end provided with a pair of free ends, said sections being secured together with their respective free end portions at opposite ends of the expander, the arrangement being such that the continuous ends of said sections engage 5 the skirt wall adjacent the ends of said opposed slots, and said free ends straddle said slots intermediate the ends of the latter.

9. In a combination with a piston having a skirt with a vertical slot at one side extending 7 from the upper end of the skirt and terminating short of its lower end and a second opposed and vertical slot extending from the lower end of said skirt and terminating short of the upper end of the latter, of expanding means mounted crosswise of said skirt and having end and side portions adapted to engage said skirt in the direction of said slots and laterally thereof, respectively, and expanding means including a device having at each end thereof a pair of free ends vertically spaced from a continuous end portion, the free ends at opposite ends of said device being vertically ofiset with respect to each other and engaging the wall of said skirt on the opposite sides of the respective of said slots with said continuous end portions also engaged with the wall of said skirt.

ROY W. PATON.

(Seal) CERTIFICATE OF CORRECTION.

Patent No. 2,023,613. December 10, 1935.

ROY W. PATON.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column, line 4, claim 9, for "and" read said; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 28th day of January, A. D. 1936.

Leslie Frazer Acting Commissioner of Patents. 

